Just when you thought it was safe to look at Facebook again, a new charity internet craze is set to sweep the web.

Sporting that crusty-eyed, wild-haired 'just woken up' look, The #WakeUpCall – in aid of Unicef – morphs elements of two of the most successful viral campaigns of recent times – the #nomakeupselfie and the Ice Bucket Challenge .

Unicef have thrown down the gauntlet by encouraging people to post snaps or videos of themselves online within moments of waking up.

Like the #nomakeupselfie it's set to offer a rare glimpse at celebrities minus their slap and give the wider world a sneek peek at the real lives of the rich.

Unicef are banking on the craze taking off – especially as both men and women can get stuck in.